The present invention relates to an apparatus and a method for aiding in designing wiring paths of a wire harness arranged in a three dimensional space, and a computer readable recording medium storing a program thereof. More particularly, the invention relates to a wire harness design aiding apparatus and a method for making it easy to determine, for example, directions and angles of branch lines branched out from the main line of the wire harness.
In various types of electronic devices of vehicles and home-use electronic appliances, line members, such as wire harnesses, are used for interconnecting electric components or packages.
Such a wire harness is constructed such that a plurality of electric wires or communication wires are coupled together into a bundle by use of an appropriate protecting member, such as a tape, and connectors are attached to both ends or predetermined positions of the wire harness.
In the design works of the wire harnesses, a CAD (computer aided design) has been widely used from an early stage as to the design of the electric components and electronic packages itself.
A known apparatus for aiding in the design of line members such as wire harnesses is disclosed in JP-A-2001-250438.
The publication discloses an object of providing an apparatus and method for assisting wiring design of line members, which computes a realistic configuration of a wire harness by using simple setting items, and reports information on it, and computer readable storage medium. Further, to achieve the object, the publication discloses “A wire harness wiring design assisting apparatus having computing means for computing, based on a plurality of fixing positions and a deformation factor of line members which are input, a wiring configuration of a wire harness, which satisfies the fixing positions of the wire harness, and for providing information on the computation result, in which the computing means computes a bending rigid E of a target wire harness by a prescribed biquadratic function of a curvature ρ of the wire harness based on a diameter φ of the wire harness, and computes a wiring configuration of the wire harness by using the computed bending rigid E.”
Generally, a wire harness wired inside a vehicle body of an automobile or the like is directly or indirectly laid along a flat wiring jig plate and is manufactured so that a branch line is branched from a main line.
By the way, generally, a wire harness wired inside a vehicle body of such as an automobile or the like is directly or indirectly laid along a flat wiring jig plate and is manufactured so that a branch line is branched from a main line.
In manufacturing the wire harness for the automobile, it is necessary to set a length of the main line to a length suitable for a wiring path of the main line, and to branch out branch lines from a number of positions on the main line since the body of the automobile has a complicated three-dimensional structure.
When the wire harness is manufactured on the wiring jig plate, in view of efficiency of manufacturing, there is a demand for restricting branching directions of the branch lines to two directions which are parallel to the main line and the wiring jig plate.
In the wire harness for the automobile, bending forces, twisting forces and the like are applied to the main line according to the three dimensional structure of the vehicle body. Accordingly, if the branch line is designed so as to be branched out with the shortest path from the main line to the auxiliary device on a CAD display (3D), the branch lines are branched out from the main line in many directions when the wire harness is manufactured on the wiring jig plate.
Accordingly, in manufacturing the wire harness, it is required that the branch lines are branched out in proper directions and the branching angle of each branch line is determined in light of the bending and twisting of the main line so as to branch out the branch lines in two different directions along the wiring jig plate.
Note that the branch line is not always branched out so as to have the shortest distance. When the branch line is branched out in two different directions along the wiring jig plate in light of positional relation to the auxiliary device, the branch line may be somewhat detoured.
The term “branching angle of the branch line” means an angle between a virtual plane that is parallel to a plane direction of the wiring jig plate and passes an axial line of the main line, and an axial line of a branch line branched out from the outer surface of the main line, when a branch line is branched out from the main line on the flat wiring jig plate.
In the general manufacturing procedure, the orientation and the branching angle of the branch line branched out from the main line of the wire harness are determined based on designer's intuition and experience, and trial manufacturing is repeated. Accordingly, the product quality depends on designer's skill.
Where the related wiring path design aiding apparatus is used, it is impossible to design the branch line so as to be branched out in an appropriate direction, while taking the bending and twisting of the main line into consideration. As a result, a wire harness is manufactured in which a branching angle of a branch line branched out from the main line is not proper, and the wire harness does not conform in configuration to the complicated three-dimensional structure of the vehicle body.
Specifically, the following problem may occur. The branch line may be too short to reach the auxiliary component or the branch line may be too long to create a sag, and possibly interferes with the vehicle body and auxiliary component located therearound.
Thus, in manufacturing the wire harness for the automobile, when the related wiring path design aiding apparatus is used, it is difficult to determine a branching angle of the branch line suitable for the three-dimensional structure of the vehicle body.